497 lines
12 KiB
C
497 lines
12 KiB
C
/*
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* syfs_dir.c
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*
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* Directory utility functions for libsysfs
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*
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* Copyright (C) 2003 International Business Machines, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "libsysfs.h"
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#include "sysfs.h"
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/**
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* sysfs_close_attribute: closes and cleans up attribute
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* @sysattr: attribute to close.
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*/
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void sysfs_close_attribute(struct sysfs_attribute *sysattr)
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{
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if (sysattr != NULL) {
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if (sysattr->value != NULL)
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free(sysattr->value);
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free(sysattr);
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}
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}
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/**
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* alloc_attribute: allocates and initializes attribute structure
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* returns struct sysfs_attribute with success and NULL with error.
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*/
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static struct sysfs_attribute *alloc_attribute(void)
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{
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return (struct sysfs_attribute *)
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calloc(1, sizeof(struct sysfs_attribute));
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}
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/**
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* sysfs_open_attribute: creates sysfs_attribute structure
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* @path: path to attribute.
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* returns sysfs_attribute struct with success and NULL with error.
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*/
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struct sysfs_attribute *sysfs_open_attribute(const char *path)
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{
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struct sysfs_attribute *sysattr = NULL;
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struct stat fileinfo;
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if (path == NULL) {
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errno = EINVAL;
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return NULL;
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}
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sysattr = alloc_attribute();
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if (sysattr == NULL) {
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dprintf(stderr, "Error allocating attribute at %s\n", path);
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return NULL;
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}
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strncpy(sysattr->path, path, sizeof(sysattr->path));
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if ((stat(sysattr->path, &fileinfo)) != 0) {
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perror("stat");
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sysattr->method = 0;
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} else {
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if (fileinfo.st_mode & S_IRUSR)
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sysattr->method |= SYSFS_METHOD_SHOW;
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if (fileinfo.st_mode & S_IWUSR)
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sysattr->method |= SYSFS_METHOD_STORE;
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}
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return sysattr;
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}
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/**
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* sysfs_read_attribute: reads value from attribute
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* @sysattr: attribute to read
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_attribute(struct sysfs_attribute *sysattr)
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{
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char *fbuf = NULL;
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char *vbuf = NULL;
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size_t length = 0;
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int pgsize = 0;
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int fd;
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if (sysattr == NULL) {
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errno = EINVAL;
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return -1;
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}
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if (!(sysattr->method & SYSFS_METHOD_SHOW)) {
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dprintf (stderr, "Show method not supported for attribute %s\n",
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sysattr->path);
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return -1;
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}
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pgsize = getpagesize();
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fbuf = (char *)calloc(1, pgsize+1);
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if (fbuf == NULL) {
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perror("calloc");
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return -1;
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}
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if ((fd = open(sysattr->path, O_RDONLY)) < 0) {
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dprintf (stderr, "Error reading attribute %s\n", sysattr->path);
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free(fbuf);
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return -1;
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}
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length = read(fd, fbuf, pgsize);
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if (length < 0) {
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dprintf (stderr, "Error reading from attribute %s\n",
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sysattr->path);
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close(fd);
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free(fbuf);
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return -1;
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}
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sysattr->len = length;
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close(fd);
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vbuf = (char *)realloc(fbuf, length+1);
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if (vbuf == NULL) {
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perror("realloc");
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free(fbuf);
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return -1;
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}
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sysattr->value = vbuf;
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return 0;
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}
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/**
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* sysfs_read_attribute_value: given path to attribute, return its value.
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* values can be up to a pagesize, if buffer is smaller the value will
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* be truncated.
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* @attrpath: sysfs path to attribute
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* @value: buffer to put value
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* @vsize: size of value buffer
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_attribute_value(const char *attrpath, char *value, size_t vsize)
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{
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struct sysfs_attribute *attr = NULL;
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size_t length = 0;
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if (attrpath == NULL || value == NULL) {
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errno = EINVAL;
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return -1;
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}
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attr = sysfs_open_attribute(attrpath);
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if (attr == NULL) {
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dprintf(stderr, "Invalid attribute path %s\n", attrpath);
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errno = EINVAL;
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return -1;
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}
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if((sysfs_read_attribute(attr)) != 0 || attr->value == NULL) {
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dprintf(stderr, "Error reading from attribute %s\n", attrpath);
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sysfs_close_attribute(attr);
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return -1;
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}
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length = strlen(attr->value);
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if (length > vsize)
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dprintf(stderr,
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"Value length %d is larger than supplied buffer %d\n",
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length, vsize);
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strncpy(value, attr->value, vsize);
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sysfs_close_attribute(attr);
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return 0;
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}
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/**
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* sysfs_get_value_from_attrbutes: given a linked list of attributes and an
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* attribute name, return its value
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* @attr: attribute to search
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* @name: name to look for
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* returns char * value - could be NULL
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*/
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char *sysfs_get_value_from_attributes(struct sysfs_attribute *attr,
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const char *name)
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{
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struct sysfs_attribute *cur = NULL;
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char tmpname[SYSFS_NAME_LEN];
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if (attr == NULL || name == NULL) {
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errno = EINVAL;
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return NULL;
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}
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cur = attr;
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while (cur != NULL) {
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memset(tmpname, 0, SYSFS_NAME_LEN);
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if ((sysfs_get_name_from_path(cur->path, tmpname,
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SYSFS_NAME_LEN)) != 0) {
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cur = cur->next;
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continue;
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}
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if (strcmp(tmpname, name) == 0)
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return cur->value;
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cur = cur->next;
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}
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return NULL;
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}
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/**
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* add_subdir_to_dir: adds subdirectory to directory's subdirs
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* @sysdir: directory to add subdir to
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* @subdir: subdirectory to add.
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*/
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static void add_subdir_to_dir(struct sysfs_directory *sysdir,
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struct sysfs_directory *subdir)
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{
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if (sysdir != NULL && subdir != NULL) {
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subdir->next = sysdir->subdirs;
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sysdir->subdirs = subdir;
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}
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}
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/**
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* add_attr_to_dir: adds attribute to directory's attributes
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* @sysdir: directory to add attribute to
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* @sysattr: attribute to add.
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*/
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static void add_attr_to_dir(struct sysfs_directory *sysdir,
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struct sysfs_attribute *sysattr)
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{
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if (sysdir != NULL && sysattr != NULL) {
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sysattr->next = sysdir->attributes;
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sysdir->attributes = sysattr;
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}
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}
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/**
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* sysfs_close_dlink: closes and cleans up directory link.
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* @dlink: directory link to close.
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*/
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void sysfs_close_dlink(struct sysfs_dlink *dlink)
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{
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if (dlink != NULL) {
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dlink->next = NULL;
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if (dlink->target != NULL)
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sysfs_close_directory(dlink->target);
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free(dlink);
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}
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}
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/**
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* add_dlink_to_dir: adds directory link to directory's links list.
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* @sysdir: directory to add it to.
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* @dlink: link to add.
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*/
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static void add_dlink_to_dir(struct sysfs_directory *sysdir,
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struct sysfs_dlink *dlink)
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{
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if (sysdir != NULL && dlink != NULL) {
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dlink->next = sysdir->links;
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sysdir->links = dlink;
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}
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}
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/**
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* sysfs_close_directory: closes directory, cleans up attributes and links
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* @sysdir: sysfs_directory to close
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*/
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void sysfs_close_directory(struct sysfs_directory *sysdir)
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{
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struct sysfs_directory *sdir = NULL, *dnext = NULL;
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struct sysfs_dlink *dlink = NULL, *nextl = NULL;
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struct sysfs_attribute *attr = NULL, *anext = NULL;
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if (sysdir != NULL) {
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if (sysdir->subdirs != NULL) {
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for (sdir = sysdir->subdirs; sdir != NULL;
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sdir = dnext) {
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dnext = sdir->next;
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sysfs_close_directory(sdir);
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}
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}
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if (sysdir->links != NULL) {
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for (dlink = sysdir->links; dlink != NULL;
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dlink = nextl) {
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nextl = dlink->next;
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sysfs_close_dlink(dlink);
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}
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}
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if (sysdir->attributes != NULL) {
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for (attr = sysdir->attributes; attr != NULL;
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attr = anext) {
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anext = attr->next;
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/* sysfs_close_attribute(attr); */
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if (attr->value != NULL)
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free(attr->value);
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free(attr);
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}
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}
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free(sysdir);
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}
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}
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/**
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* alloc_directory: allocates and initializes directory structure
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* returns struct sysfs_directory with success or NULL with error.
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*/
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static struct sysfs_directory *alloc_directory(void)
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{
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return (struct sysfs_directory *)
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calloc(1, sizeof(struct sysfs_directory));
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}
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/**
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* alloc_dlink: allocates and initializes directory link structure
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* returns struct sysfs_dlink with success or NULL with error.
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*/
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static struct sysfs_dlink *alloc_dlink(void)
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{
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return (struct sysfs_dlink *)calloc(1, sizeof(struct sysfs_dlink));
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}
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/**
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* sysfs_open_directory: opens a sysfs directory, creates dir struct, and
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* returns.
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* @path: path of directory to open.
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* returns: struct sysfs_directory * with success and NULL on error.
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*/
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struct sysfs_directory *sysfs_open_directory(const char *path)
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{
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struct sysfs_directory *sdir = NULL;
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if (path == NULL) {
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errno = EINVAL;
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return NULL;
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}
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sdir = alloc_directory();
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if (sdir == NULL) {
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dprintf(stderr, "Error allocating directory %s\n", path);
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return NULL;
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}
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strncpy(sdir->path, path, sizeof(sdir->path));
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return sdir;
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}
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/**
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* sysfs_open_dlink: opens a sysfs directory link, creates struct, and returns
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* @path: path of link to open.
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* returns: struct sysfs_dlink * with success and NULL on error.
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*/
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struct sysfs_dlink *sysfs_open_dlink(const char *linkpath)
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{
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struct sysfs_dlink *dlink = NULL;
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struct sysfs_directory *tdir = NULL;
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char name[SYSFS_NAME_LEN];
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char target[SYSFS_PATH_MAX];
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if (linkpath == NULL) {
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errno = EINVAL;
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return NULL;
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}
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memset(name, 0, SYSFS_NAME_LEN);
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memset(target, 0, SYSFS_PATH_MAX);
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if ((sysfs_get_name_from_path(linkpath, name, SYSFS_NAME_LEN)) != 0
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|| (sysfs_get_link(linkpath, target, SYSFS_PATH_MAX)) != 0) {
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errno = EINVAL;
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dprintf(stderr, "Invalid link path %s\n", linkpath);
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return NULL;
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}
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dlink = alloc_dlink();
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if (dlink == NULL) {
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dprintf(stderr,
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"Error allocating directory link %s\n", linkpath);
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return NULL;
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}
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strcpy(dlink->name, name);
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tdir = sysfs_open_directory(target);
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if (tdir == NULL) {
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dprintf(stderr, "Invalid directory link target %s\n", target);
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sysfs_close_dlink(dlink);
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return NULL;
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}
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dlink->target = tdir;
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return dlink;
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}
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/**
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* sysfs_read_directory: grabs attributes, links, and subdirectories
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* @sysdir: sysfs directory to open
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_directory(struct sysfs_directory *sysdir)
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{
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DIR *dir = NULL;
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struct dirent *dirent = NULL;
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struct stat astats;
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struct sysfs_attribute *attr = NULL;
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struct sysfs_directory *subdir = NULL;
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struct sysfs_dlink *dlink = NULL;
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char file_path[SYSFS_PATH_MAX];
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int retval = 0;
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if (sysdir == NULL) {
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errno = EINVAL;
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return -1;
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}
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dir = opendir(sysdir->path);
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if (dir == NULL) {
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perror("opendir");
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return -1;
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}
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while(((dirent = readdir(dir)) != NULL) && retval == 0) {
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if (0 == strcmp(dirent->d_name, "."))
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continue;
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if (0 == strcmp(dirent->d_name, ".."))
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continue;
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memset(file_path, 0, SYSFS_PATH_MAX);
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strncpy(file_path, sysdir->path, sizeof(file_path));
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strncat(file_path, "/", sizeof(file_path));
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strncat(file_path, dirent->d_name, sizeof(file_path));
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if ((lstat(file_path, &astats)) != 0) {
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perror("stat");
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continue;
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}
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if (S_ISREG(astats.st_mode)) {
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attr = sysfs_open_attribute(file_path);
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if (attr == NULL) {
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dprintf (stderr, "Error opening attribute %s\n",
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file_path);
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retval = -1;
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break;
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}
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if (attr->method & SYSFS_METHOD_SHOW) {
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if ((sysfs_read_attribute(attr)) != 0) {
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dprintf (stderr,
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"Error reading attribute %s\n",
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file_path);
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sysfs_close_attribute(attr);
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continue;
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}
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}
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add_attr_to_dir(sysdir, attr);
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} else if (S_ISDIR(astats.st_mode)) {
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subdir = sysfs_open_directory(file_path);
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if (subdir == NULL) {
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dprintf (stderr, "Error opening directory %s\n",
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file_path);
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retval = -1;
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break;
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}
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add_subdir_to_dir(sysdir, subdir);
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} else if (S_ISLNK(astats.st_mode)) {
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dlink = sysfs_open_dlink(file_path);
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if (dlink == NULL) {
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dprintf(stderr, "Error opening link %s\n",
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file_path);
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retval = -1;
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break;
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}
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add_dlink_to_dir(sysdir, dlink);
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}
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}
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closedir(dir);
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return(retval);
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}
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/**
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* sysfs_read_dlinks: reads a directory link's target directory. Can
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* supply a linked list of links.
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* @dlink: directory link to read.
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* returns 0 with success or -1 with error.
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*/
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int sysfs_read_dlinks(struct sysfs_dlink *dlink)
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{
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struct sysfs_dlink *cur = NULL;
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if (dlink == NULL || dlink->target == NULL) {
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errno = EINVAL;
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return -1;
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}
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cur = dlink;
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while (cur != NULL) {
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if ((sysfs_read_directory(cur->target)) != 0) {
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dprintf(stderr,
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"Error reading directory link target %s\n",
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dlink->name);
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return -1;
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}
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cur = cur->next;
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}
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return 0;
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}
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